The present invention generally relates to a Zero Insertion Force (ZIF) socket type electrical connector, and in particular to a contact structure of a ZIF socket connector.
Zero Insertion Force (ZIF) socket type electrical connectors have been widely used in connecting an electronic device, such as a central processing unit (CPU) package, to for example a printed circuit board. A socket connector generally comprises an insulative housing or base in which a number of bores or channels is defined, each receiving and retaining a conductive contact. Each bore forms an interior space that is large enough so that the contact that is received in the bore occupies only a fraction of the space . An extra free space is thus left in the bore for receiving a corresponding pin of the electronic device therein with substantially no resistance. Once the pin is placed into the extra free space, the electronic device is moved with respect to the housing, driving the pin into engagement with a resilient arm of the contact. The arm is then deflected, ensuring a stable engagement between the pin and the arm.
Some of the conventional contacts designed for such purposes have a single arm. Examples are U.S. Pat. Nos. 5,052,101 and 5,489,218. A disadvantage associated with the single-armed contact is that the pin is subject to a moment caused by the resilient force of the single arm. In addition, due to small size of the contacts and the high density of contacts arranged in the housing, the pins of the electronic device must be perfectly aligned to the corresponding contacts before the are pins are driven to engage the arms of the contacts. This is in general very difficult to accomplish.
The others of the conventional contacts take a design of double arms wherein two resilient arms extend from opposite edges of a substantially rigid base section. The arms are opposite to each other and spaced a distance generally smaller than a diameter of the corresponding pin of the electronic device. When the pin is driven into the space between the arms, the arms are deflected away from each other to accommodate the pin. Since two arms are deflected at the same time a large driving force than that is needed in a comparable single-armed socket is required.
In addition, to provide sufficient compliance of the arm with the pin when the pin is brought into contact with the arm, the arm is made to have a greater length. This reduces the extra free space inside the bore, making the insertion of the pin into the bore difficult.
Further, the conventional double arm design requires the two arms extend away from a contact in opposite direction. When the contacts are stamped from a blank of metal sheet, the contact occupies a large space on the metal sheet. This causes certain disadvantage in manufacturing the contacts and increases costs.
It is thus desirable to provide a contact structure of an electrical connector to alleviate or even eliminate the above-discussed problems.
Accordingly, an object of the present invention is to provide a contact of an electrical connector comprising two arms that are allowed to both deflect and rotate for ensuring stable engagement with a pin of the electronic device inserted
Another object of the present invention is to provide a contact of an electrical connector having arms of short dimension in order to provide a maximum ZIF space.
Another object of the present invention is to provide a contact of an electrical connector having a design allowing a number of contacts to be compactly arranged on a blank of metal sheet.
A further object of the present invention is to provide a contact of an electrical connector having two arms arranged in a staggered fashion for accommodating an improperly positioned pin of an external electrical device.
To achieve the above objects, in accordance with the present invention, there is provided a contact of an electrical connector comprising a base section having upper and lower edges and opposite side edges connecting the upper and lower edges. Barbs are formed on side edges of the base section to interferentially retain the contact in a channel defined in a housing of the electrical connector. Two support sections that are made slim and thus relatively flexible extend from the upper edge of the base section. The support sections are spaced from each other and forms a common plane with the base section. An arm that is relatively rigid extends from each support section in a direction substantially normal to the common plane. The arms are arranged to face each other. The arms are spaced from the upper edge of the base section different distances whereby the arms are staggered with respect to each other. The staggered arms helps saving space and accommodating improperly positioned pin to be engaged by the arms. A soldering section extends from the lower edge of the base section to be soldered to an external device.